Provided is a genetically modified microorganism for the production of a derivative of 4-hydroxy-2-ketobutyrate selected in the group consisting of 1,3-propanediol, 3-hydroxypropionaldehyde, 3-hydroxypropionate and 2,4-dihydroxybutyrate, the microorganism further having a gene coding for a mutant phosphoserine aminotransferase having an improved L-homoserine aminotransferase activity converting by transamination L-homoserine into 4-hydroxy-2-ketobutyrate. Also provided is a method for the production of derivatives of 4-hydroxy-2-ketobutyrate selected in the group consisting of 1,3-propanediol, 3-hydroxypropionaldehyde, 3-hydroxypropionate and 2,4-dihydroxybutyrate by culturing the genetically modified microorganism in a culture medium and recovering the desired derivative.

The invention relates to a Bacillus anthracis (B. anthracis) in which more than one secreted protease is inactivated by genetic modification. Such a protease-deficient B. anthracis has an improved ability to produce recombinant secreted proteins compared to other bacteria, particularly other Bacillus. Improvements include production of intact (i.e., mature full-length) proteins, often at high yield. The disclosure provides a B. anthracis that comprises a genetic modification that inactivates a protease of the M4 family of metalloproteases and a genetic modification that inactivates a protease of the M6 family of metalloproteases. Also provided is a modified B. anthracis comprising such genetic modification transformed with a recombinant molecule encoding a product, as well as methods to prepare and use such B. anthracis.